Belimo NFB24-SR Damper Actuator is a spring-return, fail-safe 24 V damper actuator that provides 90 in-lb (10 Nm) of torque to position dampers connected to a damper shaft. It operates from AC/DC 24 V and uses On/Off control, with two SPDT end-switch contacts for damper position feedback to building automation systems. The unit is shipped with a predefined fail-safe position about 5° from full travel, ensuring a known state when power is removed. This model is designed for direct mounting to dampers in HVAC applications; for modulation with a 2–10 V signal, see the NFB24-SR-S variant that shares the same torque and form factor.
